Magnetic reproducer and recorder utilizing endless record and automatic selecting system



Aug. 22, 1950 DE LOY J, wHlTE 2,519,725

MAGNETIC REPRODUCER AND RECORDER UTILIZING ENDLESS RECORD AND AUTOMATIC SELECTING SYSTEM Filed March 15, 1946 4 Sheets-Sheet l gvwa/wbo n DEZOYJ WHITE WM; WM

Aug. 22, 1950: I DE LOY J. WHITE MAGNETIC REPRODUCER AND RECORDER UTILIZING 12mm AND AUTOMATIC. SELECTING SYSTEM 4 Sheets-Sheet 2 RECORD Filed March 15 1946 INVEN TOR. D'sZOYJ'W/l/TE W a W A T TORNE Y5 Aug. 22, 1950 DE LOY J. WHITE ,7

MAGNETIC REPRODUCER AND RECORDER UTILIZING ENDLESS RECORD AND AUTQMATIC SELECTING SYSTEM Filed March 15, 1946 4 Sheets-Sheet 3 75 72 11), 114 FIE-w 76 z k 76 49 -Z'; I 7",.- 1 75 72 iii 72 Q 75 X 1/5" 76 M 72 6 1 5 1 75 66 6 m I 5 IQ \n 76 72 I 4 I15 76 65 114 29g 2 75 75 "n 62 an 72 Q) 76 I Q I I15 '01. w 9 76 i l 114 1/4 gwue/wto'n 4,, I 4 DELOY JWH/TE 65 W i M (J/WW5 g- 22, 1950, DE LOY J. WHITE 2,519,725

MAGNETIC REPRODUCER AND RECORDER UTILIZING ENDLESS RECORD AND AUTOMATIC SELECTING SYSTEM Filed March 15, 1946 4 Sheets-Sheet 4 DELOY \Z WH/TE Patented Aug. 22, 1950 UNITED STATES PATENT OFFICE Application March 15, 1946, Serial No. 654,580

2 Claims.

This invention relates generally to apparatus for magnetically recording and reproducing sound, and pertains more specifically to mechanism adapted for instantaneous reproduction of any of a plurality of individual sound records magnetically impressed upon steel tape or wire regardless of the station on the sound track at which the respective record is located.

The utility of steel tape and wire as a magnetic sound recording medium contemplates the movement of the tape or wire in efiective magnetic association with pole pieces of a coil assembly energized by an electric current, the pulsations of which correspond in frequency, amplitude, and period with the sound waves to be recorded. As the reproduction of such a record requires generally the reversal of the recording process, a major problem in any commercial adaptation of such equipment is to provide effective means for carrying, directing and controlling the tape or wire, which, in order to achieve the desired definition in the transcription, must be quite long due to the speed of the medium past the pole pieces of the recording coil.

Heretofore, the tape or wire has been carried on spools or reels, being shifted from one to the other through the recording head. Reproduction of sound impressions as magnetically recorded thus necessitates the preliminary rewinding of the tape or wire to place the beginning of the sound track adjacent the reproducing coil. Correspondingly, transcription of any selected portion of the record requires the shifting of the tape or wire between the spools to an extent necessary to effect the operative juxtaposition of the selected portion to be reproduced, which is not easily identifiable, adjacent the transcribing head. While the tape or Wire may be moved at a far greater rate of speed in the rewinding process, even a slight delay obviates the utility of prior art magnetic recording equipment in the applications to which the present invention is particularly well adapted.

Generally it is an object of the invention to provide a reproducing unit for magnetic records containing a series of unrelated sound impressions, embodying means by which the reproduction of any of the individual records may be initiated instantaneously or theentire group or any selected number thereof may be transcribed serially or in any sequence desired without any delay incident to rewinding of the tape or wire or otherwise, regardless of the order of the separate transcriptions upon the sound track or their individual or collective length.

Another object is to provide apparatus of the character above alluded to, adapted for utility in accomplishing split-second reproduction of a selected portion of long serially-recorded sound sequences, such as sound effects for radio productions and motion pictures, a plurality of musical numbers for commercial automatic music machines (known as juke boxes), or home recording and play-back machines and the like. For utility in juke boxes, magnetic recording equipment must be at least as responsive as present recording apparatus, whereas instantaneous response is required to make any such sound equipment practical for transcribing sound effects.

It is, accordingly, another object hereof to provide a selector switch by which reproduction of any predetermined portion of the sound track may be effected incident to closing one of a plurality of circuits identified with the different portions of the sound track, the composite switch being adapted to coordinate the movement of the tape or wire with an electrical control and indicator mechanism whereby the transcription of a predetermined series of recorded sound impulses may be accomplished incident to actuation of a single control regardless of the position of the record to be transcribed on the tape or wire.

More specifically, an object hereof is a provision of a magnetic recording and reproducing unit embodying a plurality of magnetic heads arranged in spaced relationship along an endless recording medium of steel tape or wire, the distance along the sound track between respective pairs of magnetic heads being determined by the length of each of the serially impressed separate sound records carried by the track, whereby one of the magnetic heads may be located at the beginning of each sound record immediately prior to and at the conclusion of each transcription, for selective energization in response to actuation of mechanism operable to activate the magnetic head adjacent which the recording selected for transcription is located.

Still another object is to provide a compound tension device and cut-out switch adapted for engagement with each convolution of the endless sound recording medium so as to maintain the latter under constant tension and thereby avoid vibration or whipping of the tape or wire as it travels between its carriers or between the pole pieces of the respective magnetic heads, and further functions to open the circuits to the energized recording head and the tape or wire drive mechanism in the event of fracture of the recording medium.

Another object is the provision, in apparatus of the character last above alluded to, of looking means to engage and hold each convolution of the tape or wire against movement in the event of fracture so as to obviate disturbance of the prearranged distribution of the recording medium upon the carrier elements and through the respective recording heads incident to its normal tendency to coil when tension is relieved.

Still another object is the prevision of guide means comprising a plurality of spacing ele ments to assure uniformity in the direction of travel of the individual reaches of the tape -or wire during recordation of a magnetic pattern thereon, or reproduction or erasure thereof.

Numerous other objects and salient featuresof my invention, such for example as simplicity of operation, facility of repair and replacement of worn or damaged parts, relative economy .of manufacture, and .maximum selectivity, will be apparent to those of skill in the art upon an examination of the following description read .in the light of the accompanying drawings, .in which:

Fig. '1 is an end elevation .of the assembly, showing particularly the crossing of adjacent convolutions of the tape, which occurs at each end of the unit, and the multiple reproducing head assembly;

Fig. 2 is a side elevation of the unit, but omitting the side supporting plates, and depicting the relative arrangement of the recording, transcribing and erasing ,coil assemblies, .timer mechanism, tape-tension device, and the dual brake assembly, and showing further the drive and carrying means for the tape;

Fig. 3 .is a plan view of the selector switch with the outer casing removed;

.Fig. 4 is asectional view taken on line 4--4 of Fig. 3;

Fig. 5 is 9, wiring diagram of the apparatus.

The .unit consists generally of a plurality of drumsarranged horizontally in parallel rela- .tionship over which a long endless steel tape 'or wire is carried. In the embodiment.illustrated, tape .is utilized as the recording medium, but it .will .be understood that wire may be substituted in modifications hereof. The tape is carried upon the drums in thirty complete convolutions, fifteen seriallv connected convolutions being arranged. spirally upon the drums to move, incident to actuation of :the drive mechanism, progressively toward one end of the machine'with the remaining half of the tapeprogressing to ward the other end of the drum assembly, in a manner hereinafter more fully described. .Two of the drums are journalled in a common plane to support, horizontally, a reach of each convolution of the tape. Superimposed across the horizontal sections of the tape is a multiple magnetic recording, reproducing and erasing head, comprising a separate coil assembly for each third horizontal sect on of the tape. Also included in the assembly is a composite tension and an electrical cut-out switch mechanism adapted to engage and maintain the convolution-s under uniform tension and operable further, upon fracture of the tape, to coincidentally open the circuit to the drive mechanism and actuate a structurally-separate brake and tapeholding means so as to stop the operation and lock the :broken tape firmly in position.

As a structurally-separate unit, the invention includes a composite selector switch electrically connected with the multiple recording head assembly, which includes mechanism to continuously and automatically coordinate each of a plurality of separate manually-actuated switches, identified with different respective recorded portions of the sound track, with the reproducing coils adjacent which the respective sections of the sound track are disposed when the machine is at rest, regardless of the continuouslychanging location of said individual records on the tape with respect to the various coils.

Referring now more particularly to the drawings, the numerals of which indicate similar parts throughout the several views, ill designates a suitable base member upon which the apparatus is mounted. A pair of side frame plates H are rigidly secured to the base member ill so as to extend vertically in spaced relation for the support of the principal elements ,of the unit, above alluded to, therebetween.

Interposed between plates H is a drive drum .52 having coaxial pins is extending from opposite ends which project through and are journalled in horizontally-aligned holes adjacent the top and atncorresponding ends of plates H. .A second drum I4 (see .Fig. 2), preferably of the same diameter, is similarly journalled between plates H in parallel relationship with the drive drum I2, .but at the opposite end of the supporting frame.

Directly below each of drums l2 and Madditional drums l5 and 1 5 are similarly journalled between thesupporting frame plates H, and intermediate the vertical aligned pairs of drums, five other drums .l'! are provided, mounted upon coaxial :pins H3, rotatably held in the opposed supporting plates, and which are alternately staggered to utilize to best advantage, in the interest of large tape .capacity, the space :be- .tween the rectangle defined by the four rollers 12,14, l-5rand l6. l'ls hereinabove indicated, the recording medium comprises an endless steel tape 19, which is wound around the drums thirty times so as to form thirty convolutions thereof,

with each convolution engaged with and supported by allof the drums. To this end the length of tape !9 at one end of the drive drum l2 extends downwardly .under drum l5 therebelow, and then under andoverthe staggered drums ll and thence under drum H3 and over drum l4, returning in a horizontal reach 28 to the drive drum l-2 at a point adjacent but spaced from the beginning of the first convolution thereof. The fourteen succeedingconvolutions of the tape are correspondingly wound around the tape carriers in a spiral, terminating at the opposite end of the drum assembly in the fifteenth convolution. The reach-2| of the sixteenth convolution between the drive drum I2 and drum l5 crosses the corresponding section of the immediately preceding convolution, thus initiating the reverse spiral progression of the tape through successive convolutions toward the opposite end of the roller assembly. Accordingly, it will be observed that one-half of tape [9 is spiralled toward one end of the frame and the other half correspondingly spiralled in a reverse direction with sections of I each convolution of the latter half of the tape arate magnetic records of equal length which are serially impressed upon the tape. As there are thirty convolutions of tape carried by the drums, the multiple recording head assembly, about to be described, is arranged to support one reproducing coil and pole piece assembly in operative contact with each third convolution. To this end I provide a bar 22 composed of nonmagnetic material, having its ends connected to the opposed frame plates I! so as to extend transversely across the upper horizontally-disposed reaches 2!] of the tape intermediate the drive drum i2 and drum I4. Depending from bar 22 are a series of coil cores 23 arranged in equi-spaced relation to overhang and contact the horizontal reaches 20, respectively, of each third convolution of the tape. Around each core 23 a coil of conventional construction is wound, whereby energization of the coil by a sound current is effective to polarize the end of the core in contact with the tape, The coils are identified by numerals 24 to 33. The opposite pole of each coil is shown diagrammatically in Fig. 2 below the tape as at 23c, it being understood that in accordance with corn ventional construction each pole 23a of the corresponding coil is connected with the upper end of core 23 around the tape so as to be of opposite polarity and attract the magnetic flux emanating from the lower end of the adjacent core 2 One of the pins I3 of drive drum l2 projects through one of the frame plates H and has mounted thereon a pulley :34 over which a belt 35 extends for transmission of rotary motion from a suitably located electric motor 36. Actuation of motor 36 is thus effective to drive the tape I 9 over the various drums at high speed, the direction of movement of the upper horizontal reaches of the tape being from left to right as seen in Fig. 2. It will be noted, however, that alternate reaches of the tape overlying the drive drums and which are inclined, parallel to one another, in one direction (Fig. 1) comprise onehalf of the tape and are serially connected, while those reaches inclined in the opposite direction and comprising the other half of the tape are correspondingly connected in series. The two differently spiralled halves of the tape are connected at the ends of the tape-carrying drums.

Thus, at each end of the apparatus the convolutions 3'! composed of one-half of the tape which I are spiralled in one direction overlap convolutions 33 comprising the other half of the tape spiralled in the opposite direction. To avoid friction between the overlapping reaches of tape I9, I pro" vide at one end of the assembly (see Fig. 2) a rod 39 having its ends rigidly mounted in the frame plates l and extending between the outer overlapping reaches of each of the convolutions 3? of tap-e 1e and the inner lapped reaches 33, so as to prevent any contact between these sections of the tape.

At the opposite end of the unit a bar 45! composed of dielectric material having its ends secured to the side frame plates extends across the lapped and overlapped reaches 38 and 31, respectively, of the tape intermediate the drum l4 and the drum I5 therebelow. A plurality of phosphor bronze spring members 4| (fifteen in the embodiment illustrated) of a composite tensioning device and cut-out switch 59, are each secured at one lower end to bar 4|) in equi-spaced relationship in positions slightly offset respectively from the overlapping sections of convolu-' tions 3! at that end of the assembly. The upper end of each member 4|. extends toward the adjacent reach of the tape and carries a short lat erally-projccting rod 42 that engages behind the overlapping reach of the tape adjacent which it is disposed. Each spring 4| normally exerts a lateral tension upon the tape to hold it out of contact with the vertically-disposed lapped reach of the convolution 38 of tape thereunder.

The tape 19 is sufficiently taut to extend each of the springs 4| into contact with an adjacent terminal 43 suitably supported at the opposite side of each spring 4| from bar 40, which with the springs are arranged in the circuit to the drive motor 36, as will appear. It will be appreciated that if any convolution of the tape breaks, the tension of that convolution will be immediately relieved, whereupon the spring 4| engaged therewith will snap out of contact with the ter minal 43 opening the circuit to motor 36. The assumption of the more-nearly normal position of such spring 4| engaged with the broken convolution of the tape thereupon causes its upper end to contact a terminal 44 carried by the bar 40 and completes a circuit through actuating mechanism for a tape-locking device and an independent roller brake, about to be described.

It will be observed that the function of the rod 39 and of the various springs 4| are complementary to one another as they tend under normal conditions to equalize not only the length of the convolutions with respect to one another but also cooperate in maintaining the tension throughout the length of the tape substantially uniform.

The double spiralled arrangement of tape I9 is maintained during operation by a plurality of guide assemblies, one of which is arranged to engage all of the vertical reaches of the tape, leaving drum l2. The other guide assemblies similarly engage, respectively, other vertical'reaches of the tape, moving from each of drums 5, I6 and IT, respectively. Additional guides maintain the proper angular disposition of the reaches of thetape extending obliquely outward from the drive drum I2 and drum I6, respectively. The guide assemblies are substantially identical in construction, and it will be understood that the following description of one thereof applies also to each of the others. Each composite guide comprises a rod 45 having its ends secured in opposite frame plates I! so as to extend therebetween in parallel alignment with the drums. A plurality of disks 4%, equal in number to twice the total number of convolutions of tape l9, are arranged on rod 45 in pairs, the disks 45 of each pair being spaced apart a distance equal to the width of tape H? by spacers (not shown) so as to engage opposite side edges of the length of tape in alignment with which they are disposed, respectively. The diiferent pairs of disks are accordingly spaced apart by sleeves 4! encircling the rod 45. Sleeves 47 are each of a length corresponding to the proper equal spacing between the reaches of the tape extending thereover. Inasmuch as tWo guide assemblies are provided for the lapped and the overlapping reaches of the beia'yecnadjacent 'coi-lsZB and 29 and coils 33 and .IL-respeotively. it will be appreciated that up transcription of any one or the records all records-will have advanced. to a position immediately preceding the nextseriallyarranged coil. -E.. g., as'the "first record above alluded to moon the 'tape between coilsgt33 and 12-4 is transcribed, that length of tape will have progressed to a point intermediate :coils 2.4 -1'and.:25, and all other records will have :been advanced-tea corresponding extent. Accordin ly, teach transcription (of any of the records) results inthe juxtaposition of all records adjacent the next succeeding coils.

:In ,orderto -.enable the selective actuation of the coils :for the reproduction of :any of the-records icarried'aby'the tape or any c p her f in any sequence-desired by the operator, I provide a -compound rotary -;selector switch assembly #12 which is efieotive to coordinate automatically the indiridual operations of :any of a series or manually-controlled switches illustrated diagrammatica-lly in Fig. and identified: by numer sis 451 tofilL-with-the energiaation of the reprodocing coils that are momentarily positioned (at the beginning of the records by which said respective :switches :54 to so are permanently identifled. Switch 48 illustrated most clearly in 3 and; comprises acasingconsis-ting of plates of and 52 supporting :coaxially aligned bearings -53 'iorthe supporter 1a shaftet l, adapted to be retated in synchroniaationwith the operation of the tapeecarryi-ng vdrums, as will appear Between plates at! and-fi2,-a flat annulus 55, composed of asuitable dielectric, held'ina central plane equi-distant from the respective platestl and 2 lay-interposed spacers 5,6, throughwhich elements bolts 6'! extend to hold the assembly together. One end oi shaitt l projectingfrom thelcasingcarries apulley .58 to which power is transmitted fromthe drum M throughpa belt pulley-ascend an interposed speed reducer (not shown) whereby shaftt is compelled to complete-a :single revolution --w-ith each complete -cy ole-of movement 'of'the-entire tap-e; i.- e., with each morementwcf the tape through all ten reproducing .ooi'l assemblies 24 130.33. It-will be-understood that the :means shown and described for operating andasynohron'izing switch so with the movement of tape) is merely illustrative of any conventional ;apparatus,;gand that the switch so may be actuated directly from motor -36 through suitable reduction gearing, or a separate motor mayibeemployedfor-this purpose, and that the essential synchronization of the movement of the switchshaft t4 and tape 19 maybe accomplished electrically if desired.

,Mountedupon the shaft within the casing is a flat disk composed "of a dielectric material, to one side of which are secured by suitable means ten concentric brass rings H. The annulust5 is otawidth sufiicient-to project into the casing. and :ailord support for ten resilient spring contacts .12 which are c'qui space'd around the ii axis (ii-shaft t4. FIfhespring-eontaets Hareeach oi-di-fierent lengths, to slidably engage and maintain contact with different rings H. At th o e-- posite side of disk NJ-a second group of ten concentric brass rings 73 are secured in transverse alignment with the rings,- 'll to which they are connected respectively by pins l4 extend-ing' through dish "it. Each of rings '53 is provided with an integral radial extension 15., varying in length in inversed proportion to the difierence in spacing of the respective rings "53 of which they are a part from the axis of the assembly whereby the outer ends of the extensions all terminate slightly beyond, the periphery of dish 18. Secured to the corresponding side of annulus 65 and projecting radially inward into the arc of movement of the outer ends of extensions 15 are ten terminals l6 arranged around shaft 64 in equi-spaced relation whereby-thev spring contacts .12 and terminals l5 are alternately disposed. Rotation of shaft 6 5 results in maintaining electrical communication through the rings?! and 73 between the springs '52 and the radialextensions Hi, which latter, with each record transcription, are shifted circumrerentiallyinto electrical contact with the next suceeding terminals 16. Each terminal 16 is connected with an individual conventional solenoid-controlled relay mechanism as hereinafter described (see Fig, 5), to complete an auxiliarycircuit through a reproducing coil for a period determined by a. conventional timer, as is hereinafter described more in detail. The relays are identified bynumerals '58 to .31.

It will be understood that the manually-actuatedswitches 5| to 6,0 may bearranged ina panel (not shown) adapted to support indicia desi mating the separate magnetic records carried serially on the tape. While the location of the record along the, length of-the tape with respect to the various reproducing coils varies with each transcription, and while this factor is compensatedior by the selector switch lfl, it is essential that the vsuocessionof the magnetic records on the tape be in accordance with the arrangement of switches .5! to 156 identified therewith, respectively,.on the panel in order to assure the selectivity requiredas will be obvious. Thus, as each terminal it is identified with a particular reproducing coil, it is necessary that the compound switch 49 be. preliminarily adjusted to position the respective ring extensions 1-5 in contact with terminals 6 for energization, of the coils adjacent which the records on the tape, corresponding to the respective switches, are located. For example, if the record intended to be reproduced by closing switch 5! is initially placed between coils 33 and 24, reproducing coil 24 must be connected with the amplifier 43 in order to effect the reproduction of that record. This requires that the compound selector switch 49 be preliminarily adjusted to engage the ring extension 15, connected with switch 51 ,through the rings 3H and 73 and spring contact 12, with the terminal 76 that is operable to close the circuit through coil 24 and the amplifierdfl. Such arrangement-of the switch 49 automatically positions the other extensions 15 of rings 73 connected to respective switches 52 to 6B in contact with the relays '59 to S? that controlthe connection between the other reproducingcoils'25 to 3-3 and the amplifier 48. The closing .ofswitch 5i thereupon momentarily completes a circuit through selector switch 49 and the relay [8 whereupon coincident movement of the entire tape under the corresponding repros ducingcoil .24 .is effective to .audibly reproduce the sound corresponding to the magnetic pattern of the first record through the amplifier and loud speaker assembly (Fig. At the conclusion of the first transcription the circuit through the first coil 24 is then broken by a timer 88 that is arranged in and controls the circuits through each reproducing coil and the amplifier.

The transcription of a single record will have resulted in the advancement of each record to a position with its beginning juxtaposed adjacent the next reproducing coil, and coincidentally the ten ring extensions will have been moved intocontact with the corresponding terminals 16 of the selector switch 49. The apparatus is therefore automatically set for reactivation. The same first record may again be reproduced by closing the same switch 5| with which that rec- 0rd is identified. However, due to the shifting of the selector switch 49 the circuit will be completed through the second terminal it and the second coil adjacent which the first record is at that moment located. In this manner the selector switch continues through successive operation to coordinate the operation of the respective switches with the shifting of the magnetic records carried by the tape relative to the several coils.

As hereinabov-e indicated, each third convolution of tape it passes, during operation, between the opposed pole pieces of a reproducing coil at very high speed. This requires that additional support be provided for the tape at each side of each coil assembly. To this end I provide a pair of elongated stabilizing rollers 89 at each side of points of contact by the pole pieces, the rollers 89 of each pair being disposed at opposite sides of the tape and offset slightly in the direction in which the tape extends. Rollers 89 are rotatably supported by coaxial trunnions 9t journalled in the opposite side frame plates l I. The pair of stabilizing rollers 89 disposed above tape [9 are offset inwardly from the rollers below the tape, and the lower arcs of their peripheries extend below the upper surface of the complementary rollers so as to maintain tension upon the section of each convolution of tape engaged by the pole pieces of the respective coils. In this manner, each horizontal reach of tape is supported in a fixed plane so as to minimize wear upon the pole pieces 23 and 23a. Anoth r advantage of the stabilizing rollers 89 is that, incident to their friction upon the tape, substantially all slack is obviated in the horizontal reaches '28 thereof, which, upon application of power to the drive roller it, might otherwise result in snapping the very frangible tape.

As hereinabove indicated, one of the features of the present equipment is the speed with which the apparatus responds to the actuation of the various switches 55 to Gil. In order to maintain this advantage during successive operations, and further to assure the continuance of the initial identity of the records transcribed with the respective switches 51 to G8, it is essential that the movement of the tape be stopped promptly after each reproduction, with the beginning of all magnetic records juxtaposed adjacent the coil assemblies, respectively, by which such records may be selectively reproduced during the next succeeding operation of the apparatus. To this end I provide brake mechanism, indicated generally by the numeral 9|, for the drive drum [2 comprising a pulley 92 mounted on pin l3 projecting from one end of drive drum l2 for operative engagement by a band 93 having one end secured to a suitable stationary support 94 1at-' erally f pulley 92. The opposite end of band 93 is secured to the core 95 of a solenoid 96 by a helical spring 91. Solenoid 95 is adapted to retract core 95 upon energization so as to resiliently tension band 93 through the spring 9i and apply sufilcient friction upon the pulley 92 to immediately stop the drive drum [2 and tape.

Tape or wire of the type adapted for use in magnetic recording is exceedingly thin, frangible, and resilient. In an embodiment such as that illustrated, capable of carrying a total magnetic record for a thirty minute transcription, approximately 4,206 feet of tape are employed. Should the tape break, the entire length thereof tends to leave the drums and guide assemblies, and become tangled, making a diificult task of rearrangement and repair. To largely obviate this result from a fracture of the tape, I provide a tape-locking device 93 comprising a roller 99 journalled between brackets tilt, pivoted to suitable frame supports ldl', with roller 99 disposed adjacent and parallel to but laterally of the lower drum i5, whereby the roller as may be swung against the adjacent tape-carrying drum and upon the convolutions of tape passing thereover. A helical spring 502 interposed between the end of each bracket {9%} in which the roller 99 is journalled and the adjacent frame support iiii tends to urge the roller into contact with the tape on drum i6. Adjacent each end of roller 99 a solenoid 583 is mounted, having a core 104 extended into engagement with a recess H35 in the adjacent bracket its to normally hold the roller 99 in inoperative spaced relation with respect to the adjacent tape-carrying drum la in opposition to the urge of the spring 532.

An idler roller :66, journalled between the side frame plates ii, is positioned to rotate against the tape overlying one of the tape-carrying drums I! to further resist displacement of the tape in the event of breakage. Additional idlers (not shown) may be arranged in contiguous relation with other of the tape-carrying drums if desired, and will be obvious.

With particular reference to the wiring diagram of Fig. 5, the operation of the present embodiment of my invention is briefly described as follows: Power for the unit is supplied through a lead I01, and I08 in one of which a manuallyoperable switch I69 is located adapted to be opened while servicing the equipment. Across the leads It? and I08 a lamp He is connected by wires HI to illuminate the interior of the cabinet (not shown) in which the apparatus is carried, when switch 39 is closed. An auxiliary switch H2 in one branch wire Hi controls the circuit through lamp l H).

With tape [9 arranged for immediate transcription of any of the magnetic records impressed thereon by the reproducing coils, the operator first selects the particular record he wishes to hear from the indicia accompanying the respective switches 5| to 69. Each of these switches is connected to the source of power by leads H3 connected to wire 56?, and with the selector switch 49 by leads lid whereupon closing of any thereof is effective to pass a current through the spring contact and ring extension F5 corresponding therewith to the terminal iii with which the latter is engaged, and thence to the solenoid of the relay corresponding to the reproducing coil which is juxtaposed at the beginning of the magnetic record to be reproduced through wires H5. The solenoid of the relay is ejeeme l1 per ble to; c hheet. th repres he he will thetepel-leehh edeyi ee Q thefeheh eede ifilehs which i ese ted: w h e am lifier 46 w is e e thhi eh eeds Hi ehsiflvires 11 Uheh fe t elbl ele ese 'he' e est ehe an we e h .hele s H0. :1 the be, teheieh. e the 5 Ei $.-m Y. Ufiehh .eh. h .tih.1. 8 2 ;e eeeqe hih h the 5 e heb th e -Je hh epe :r-shne drum. I

it eh-l remit-"e; eenhe, ei-v Qhe he Q v he mer hich slefi e e l ei ene L. .x e ,9 threueh h. c Q ter 36 eterh ew of Whiehh pehee ekq tel eeq hd eetee h ereei ei ee ll xist hol -1 nie 10. 1, eh lther h She i h hevemeh h em a semble hehe s ee. henlatera s QX QB iQQ; 221i heeh et with wh h he ele h eeeehe hhsi. 1. 1 hi; e. a t reptqeeeihe 9 .4;. The u t. PlTQ UQ QQ e011, .1 1 ht. hi e fifi? i l ehzh hhe ee ehj th he, emehhee. ere 1-2.3; q-z hj he h h h r 8 01 165 1 6 ht u t h e1 "cl s d e h rak e e q d .5 qehh e eq e e "ll se es; te el e e; h e-35 9*!!! 2f? e e-els ehd 9 v hen e Pe et 9 1 f: he d i drh Th e w eh. the; em: hdt me etret is d ust d ee er; eh ii H9 th ough motors; andfclos elthe ci ouit 0 toltherbrake mechanism 9| at th e end. ofe thr ee minute inteitveL which is the time reg i 'ed fog hi he he e h e r ine- A fh ht' wit '2": e hhd t sw t h o he" i e 8 ,ee '1}; r ll d y n h r h v h h lyth edSwit 25 r p e h t l d by: th tepemey-be; erased. 3A p i ed by c s n f thi l Qh we e;-;new 11eoordimpressed thereon simultane h hs ersg' he timer mechanism mp r ti e h duly'bi'bnetf coils 24%0 h e m hhe he hhre m e ice r or ny egtngled portion. thereof carried by the whole e'ma' be reproduced Without'interruptio A co plete mzignetio pattern is initially impresseq u p ori the tape by energizing any one of. the coils; igg'zigle t to closing, orie of switches 51 to 69., threu h m fi r. 8. 5 e Sound eht end. P e h' th f a e h h which thereof, tobe use d as a soufngl track in'contgct with the pole pieces of the energized coil. The Switch 2?.; r ehedte is m ihte hedeihele e 29 19?! d l-Z n Qe i t r er ehe hi diiantity oi tape suffigient for approximately e -P ee e 40 there hinee i e -cq emi use w pe n will 1? Q P P Y Q w h 3 15, a an e teemmma thatiiumerous chahg es'in siz e,.d QRWXWWY c rc Wl me r h h ee Sign)"shabend huniber or.'thevaiibusiiareglmay 293% filen n e'e rdehe w th eh qhelz beiinaa,anaittrmtmiyi the), ariah'riirit are ehfiwefieh s er ive eutrh h he m riiimbi of imitate-earning. 'ioiii s 'r'hey ii as long as a coin is in the switoh Aooorglingly, h" fi fi j fi ih sj R-QWWEIEWW til ihg h Q9 herete ewite the time; will not open the oigcpit'to them 3. hdw ll hehe hvete. th b ak m eheh m eeff e ei he, h hin meihe h h sw tch hhee. e e e n ay be eeedi mu tan h y wthih h witch d he mee ine, wil sheees l rehredve he r Sele ed. b actuation of the switohes 5lto; Silentilell of ete fl: ht efh hel o separate ecordin me ums; y: he s st tut or he sin le. tape;

of the series of coins passes through switch I23 1! .7 Y 1 e 1. e em er xeted: sineludme ructhe timer 88 1s again out into the, c lfc u t s qas q 1y sggamtg tapeflqli wjmmcgrding dementa hi meter h d a u e hehreke 1 t h h .tI-claim and-'desir ,-et se e helheieh li h oll wing th e m nute nehq 0 Eli a 5 Cum hlt h d i 5' c0111 aehetieound? e hipment: i he char:

heer in l 43, ndt prin f m mb 391! ast l de. rioedan endless recording medium a ehsieh wi ch 9 ere e nee ed er e with p'ag bifolleifi tosh port;saicl1reootdingr.mediiim, eatnother and wlth the swl eehe eme aipluralityzoi magnetic reproducingeheadsfspaced h 1m? 3- hm h ea s 259mg tem. .5 along said meeord-ing medium. with; the. sections QQYQ V-t P of 17 ene b k n: the e ion of tlielatt ter ihterposefi betweeneadioiningrheads the. av 129 1 h in m r. a tid bing of"diiatiength. mm magnetic records EQQQP h r eh. is ell ee l e h e ceifiediby saidseparate sectionsoil-said;fecoriiiz wee e in 4' n e nal-4 h n h he; mg 'rngmilm met 'm; move; saidrecording, the t he heh h timer 88 to e m ter: Q rhfe um mfeug fl-s'lal heads; aypmrtieyl of =e1 ee= a$t-StQPthe1atterh relief tensim e. ll ht el f l-tifiedz withisaidireords; m; 1 .1 of e emembe 4| o erm e spec ti vel y, encl'm .nsqineludir g mselector switch spring to contact terminz l 4 4, completingithe cir-H a m m hit hhrehe h i h h r h eh h b -en of e ireee rfi es'pbnse h zh en e-ie eeh hes lehhi ei wh t .9 1e .1 ;ifieg1:there=,

13 with, respectively, through the reproducing head nearest adjacent the beginning of the record on the medium regardless of the position of said record with respect to the rollers.

2. In magnetic sound equipment of the character described, a recording medium, a. plurality of recording heads operatively associated with said recording medium and arranged along the length of the medium in equi-spaced relation, means to move said medium through said heads, an amplifier, the length of said medium between the different pairs of said coils carrying separate magnetic records of sound impulses to be reproduced, a plurality of electrical controls identified with said records respectively, and a selector switch synchronized with said firstnamed means and actuated in response to activation of any of said controls to connect the reproducing head disposed nearest adjacent the beginning of the record identified with the control activatednvith the amplifier.

DE LOY J. WHITE.

14 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 909,414 Hytten Jan. 12, 1909 1,040,768 Ryon Oct. 8, 1912 1,123,147 Sherman Dec, 29, 1914 1,166,925 Ober Jan. 4, 1916 1,461,528 Irvine July 10, 1923 1,934,320 Nowosielski Nov. 7, 1933 1,968,166 Pythian 'July 31, 1934 1,990,643 Fankboner Feb. 12, 1935 2,177,481 Hall Oct. 24, 1939 2,209,157 Glunt July 23, 1940 2,258,651 Hooland Oct. 14, 1941 2,269,952 Morgan Jan. 13, 1942 2,317,310 Stern Apr. 20, 1943 2,327,956 Begun Aug. 24, 1943 2,335,277 Heller Nov. 30, 1943 2,349,018 Tasker May 16, 1944 2,356,145 Begun Aug. 22, 1944 

